Combined steel and concrete beam.



No. 768,284. PATENTED AUG. 23, 1904.

' v J. KAHN. I

CGMBINED STEEL AND CONCRETE BEAM.

APPLIOATION FILED JAN. 20. 1904.

N0 MODEL. 2 SHEETS-SHEET 1.

PATENTED AUG. 23, 1904.

JpKAHN. COMBINED STEEL AND CONCRETE BEAM.

APPLICATION FILED JAN. 20' 1904.

2 SHEETS-SHEET 2.

NO MODEL.

WKN b, 9%

Patented August 23, 1904. i

PATENT OFFICE.

JIILIUS KAHN, OF DETROIT, MICHIGAN.

COMBINED STEEL AND CONCRETE BEAM. g

SPECIFICATION forming part of Letters Patent No. 768,284, dated August23, 1964.

Application filed January 2i), 19051. Serial No. 189,798. (No model.) ll To @ZZ whom, t may concern:

Be it known tliatl, JULIUS KAHN. a citizen of the United States,residing at Detroit, in

` for said beam supplemented with washers or deformations to insurebetter contact with the concrete body and to preventstripping.

A further object of my invention is to construct the main tension-barofuniform crosslsections in order that there may be no waste of materialand to enable the use of a greater or less number of washers, as may bedesired.

These objects I attain by the construction.

and arrangement'of the parts, as illustrated in the drawings, and setforth in the description and claims.

In the accompanying drawings, Figures'l,

2, 3,' 4, and 6 are views of a bar constructed in accordance with myinvention, having washers of diiferent forms. Fig. 5 shows a tensionmember in thel form of a twisted square bar.

' Fig. 7 isa longitudinal section of the beam with the'tension member inposition. Figs. 8 to 13, inclusive, are cross-sections of the Y tensionmembers shown in Figs. 1 to 6, inclua square bar molded to give a roundcross- Y Fig. 16

17 is a similar bar twisted.

sive, respectively. Fig. 14 is across-section of the beam shown in Fig.7. Flg. 15 shows y the bar shown in Fig. 1. Fig. 19 shows a beam withthe tension member of'Fig. 17 in` position.

tension stresses. This bar is provided at points intermediate its endswith the washers B, which may be used in any desired number and placedat any desired distance apart, either uniformly spaced lor preferablycloser together at the ends ofthe bars. These wasliei's B, as shown inFigs. 8 and 18, are square,

with a circular opening in the center to fit on the bar A, which willalso be circular in crosssection. After the washers have been placedmation of said bar (indicated by H) is made on either side of thewashers for the purpose of holding them securely in position by placingthe bar between two pairs of dies, the washer being between the pairs.Then the dies are closed, aportion of the bar is squeezed out radially,soas to form a lug or vear H on each side of the washer, thereby rigidlysecuring the washer in place on the bar without reducing' thecross-sectional area. These lugs are preferably formed in pairs, one oneither side of the bar. The washers may be of any shape or size, asshown in the various figures, depending upon the-shape and load of thebeam.

Where square bars are used, either straight or twisted, I` prefer tochange the cross-section at the point of alteration of the cross-sectionfrom vsquare to round, as shown in Figs. 15, 16, and 17 which may bedone by using cylindrical dies. The diameter of a circle of unit areais1.13, 'so that four strong lugs or shoulders M will be formed on the barN on either side of the washers. The bar may be twisted either before orafter the alteration of the cross-section; but I prefer to twist the barafter the washers are secured in place.

As shown in Fig. 5, the bar K is provided with vspiral corrugations,which greatly increase the adhesion of the concrete. The washers in thisfigure are represented of varying sizes, smaller at the middle of thebar and increasing in size as they approach the ends.

For the purpose lof serving as binders for the concrete these washerswould preferably be Similar reference characters refer to like maderectangular or oblong and the greater length placed'in a vertical lineof the beam L. They may extend perpendicularly to the mainl longitudinalbeam or may be inclined obliquely thereto, as represented in Figs. 6 and17. In this modification the washers best perform the function ofbinding the concrete againstsheering stresses and at the same timeprevent the bar from stripping. It is -oii the bar anupsetting,distortion, or deforg IOO not necessary that these washersshall be of great weight or strength, but are preferably constructed ofa comparatively light material.

The adhesion of concrete to a plain bar is considerable, but notsuflicient in all cases to make a beam of symmetrical strength-that is,one in which the adhesion of the concrete necessary to preventstripping` will equal the tensile strength of the longitudinal metalbar. By the use of my invention these factors may be provided for asparticular cases demand a'nd the highest efficiency obtained by thereinforcement.

To form the beam, the tension-bar is suspended or otherwise supported inand near the bottom of the mold and concrete rammed around it, whichwhen setting unites with the tension member, forming a beam of greatstrength, the tension member being below the neutral axis of the beam.

Having now explained my improvement, what I claim as my invention, anddesire to secure by Letters Patent, is-

1. In a metal reinforcement for concrete, the combination of a tensionmember, of a plurality of metal blocks or washers placed upon the memberat points intermediate its ends, said Washers having arms projectinglaterally from one side of the member, the cross-section of said memberbeing changed to form shoulders for the support of said blocks. 1

2. In a beam, the combination of a tension member of uniformcross-section and uniformly twisted, of a plurality of auxiliary piecesplaced upon said member at points in? termediate its ends and inclinedin opposite directions from the center and secured in position bydeformations of said member on the opposite sides thereof, and a beam ofplastic material surrounding said member.

3. ln a beam, the combination of a longitudinally-disposed tensionmember, of auxiliary pieces placed upon said member at pointsintermediate its ends and secured in position by deformation of themember without varying its cross-sectional area, and a beam of plasticmaterial surrounding said tension member, the tension member being belowthe neutral axis of the beam.

4. In a metallic reinforcement for concrete, the combination of ametallic bar longitudinally disposed, of auxiliary perforated membersstrung upon the bar and secured in place, said auxiliary members being'inclined in opposite directions from the middle of said bar.

5. ln a metallic reinforcement for concrete the combination of a bar,rectangular in crosssection, and washers on said bar having rectangularopenings, said bar being molded to eil'- cular cross-sections to formshoulders to support said washers.

6. ln a metallic reinforcement for concrete, the combination of atwisted bar, rectangular in cross-section, and washers on said bar, saidbar being molded to circular cross-section to form shoulders to supportsaid washers.

7. In a metallic reinforcement for concrete, the combination of a bar,rectangular in crosssection, and washers on said bar hav i ng reelangular openings and being inclined in opposite directions from themiddle of said bar, said bar being molded to circular cross-sections toform supportiiig-shoulders on each side of said washers.

8. In a metal reinforcement for concrete, the combination of a tensionmember, of a plurality of metal blocks or washers plaeed upon themember, at points intermediate its ends` and of a deformation of saidmember without varying its cross-sectional area whereby a shoulder isgiven for the support of said blocks.

9. ln a reinforcement for concrete or similar material, the combinationof a longitudinal bar of uniform cross-section, of a plurality ofwashers placed upon said bar at points intermediate its ends, andsecured against longitudinal movement by deformations of the bar to formshoulders on opposite sides of the washers which distortions do not varythe cross-sectional area of the bar.

10. In a metal reinforcement for concrete, the combination of a tensionn'iember, of a plurality of auxiliary members placed upon the tensionmember intermediate its ends, said auxiliary members having armsprojecting laterally from one side, the cross-section of said tensionmember being changed to form shoulders for the supportf said auxiliarymembers.

ln testin'iony whereof l have signed my name to this specification intheprcscmzeoftwo subscribing witnesses.

JUL'IUS HAHN.

Titnessesz EDWARD N. Pai-netsw, MAURICE GoLnuNmme.

lOO

